Design a strategy to include a mix of local and cloud snaps on StorSimple + backup and retention frequency on DPM to meet your 3 goals above.

For example:
If your data set is 1 TB with anticipated 25% annual growth, and your RPO is 6 hours, and your RTO is 2 hours, and DR plan calls for offsite full backups, the following plan may be implemented:

Create new 8 TB volume on StorSimple, and present it to your DPM server (create ACR record in StorSimple that points to your DPM server’s IQN)

This volume size allows for 4 years’ worth of anticipated data growth (the math will become clear in a moment). You can make the volume size much bigger like 64 TB since volumes are thin-provisioned on the StorSimple device, but this is not recommended since it will negatively impact snapshot write and read/recovery operations where the entire volume metadata will have to be read/written each time.

Keep 1 volume in a volume group. This is extra overhead during initial setup but it enhances your RTO, since StorSimple protection policies apply to volume groups not individual volumes.

Setup backup frequency to do a full backup every 6 hours in DPM. This meets the 6-hour RPO. StorSimple does an outstanding job deduplicating this data in real time (not a scheduled task)

Setup data retention on DPM to 1 day or 4 backups only. This will use 4 TB on the volume with room for anticipated growth of 1 TB or 25% annually

Setup a protection policy on the StorSimple to do a weekly local snapshot, and pick the M,T,W,T,F days – max snaps = 15. This will keep 3 weeks worth of backups. You should be using a StorSimple model with > 4 TB of local storage like the 7020, 5520, or 7250. You can use more than 15 snaps for this local daily protection policy if you have the 5520 (11.2 TB local storage) or the 7520 (22 TB local storage). This policy meets the 2-hour RTO (restoring from local storage on the StorSimple)

Setup a second protection policy to do a weekly cloud snapshot on Saturdays – max snaps = 5 to provide a month worth of weekly backups.

Setup a third protection policy to do a monthly cloud snapshot on Sundays – max snaps = 24 to provide 2 years worth of monthly backups. The last 2 policies meet DR requirement.